WASHING THE FIBERS FROM FOAMS FOR HIGHER YIELDS IN FLOTATION DEINKING

The purpose of this work was to evaluate the possibility of washing pu lp fibers from a flotation froth. A steady-state froth column was crea ted in which the formation of foam balanced the collapse of foam. Dilu te pulp and wash water were sprayed on the top of the froth, and measu rements were made of the concentration of fibers that broke through in to the liquid area below the froth. The results showed that it is poss ible to increase pulp yield in deinking flotation by washing the froth . A minimum wash water flux is required to keep fibers out of the frot h. A mechanism is proposed to explain how fibers are washed from relat ively dry froths.